For example from WO00/30458 and WO2004/002229 an installation is known for the production of shaped food products from a pumpable mass. This installation has a moulding device with a frame and a mould member having multiple mould cavities, each having a filling opening for the introduction of foodstuff material into the mould cavity. The mould member is movably supported by the frame, and a mould member drive is provided for moving the mould member along a path, the path including a fill position for filling the mass into a mould cavity and a product release position remote from the fill position for releasing a moulded product from the mould cavity.
In order to introduce a portion of the mass into a mould cavity, a mass feed member is supported by the frame and has a mouth at the fill position along the path of the mould member. The mass feed member is connected to a pump via a fill tube. The mass feed member is adapted to transfer the mass into a mould cavity of the mould member when the filling opening thereof is in communication with the mouth at the fill position.
The known installation also comprises a hopper that is adapted to receive a batch of the mass of pumpable foodstuff material, e.g. ground meat that is produced in a grinding process using a meat grinder. The mass is discharged from the hopper via a positive displacement pump that is positioned between the hopper and the fill tube to which the pump is connected. In general the pump has an inlet to receive mass from the hopper and an outlet connected to the fill tube. The pump forms one or more pump chambers that each are successively in communication with the pump inlet for the introduction of mass into the pump chamber and with the pump outlet for the discharge of mass from the pump chamber.
In the production of moulded food products with an installation of this type, e.g. for the production of shaped meat products from ground meat, e.g. from beef, pork, poultry meat, many properties of the finally obtained products are monitored as they are considered relevant. For example the weight of the moulded products lies desirably within narrow tolerances, e.g. for hamburger meat patties supplied to large fast-food establishments.
It is known to use—in the installation of the type discussed above—a controllable vacuum assembly that is adapted to cause evacuation of air that is dispersed and also available as (macro) air pockets within the mass, the evacuation taking place at one or more locations in the trajectory of the mass from and including the hopper to and including the pump chamber at a position where it is in communication with the pump inlet. For example it is known to use a combination of a positive displacement pump, e.g. a vane pump, and a vacuum pump, which combination is often part of a vacuum filler used for production of sausages, wherein a ground meat mass is stuffed into a sausage casing. The evacuation may already take place in the hopper, commonly the hopper being provided with a lid or access valve to allow the creation of a vacuum in the hopper filled with the mass. As an alternative, or in combination with evacuation of the hopper, it is known to create a vacuum in the pump, e.g. near the inlet of the positive displacement pump. e.g. such that the vacuum assists the flow of mass into the pump chamber via the inlet of the pump.
In the practice until now, as is also common for sausage production, the meat mass is evacuated as much as possible by the vacuum assembly. This is commonly done by the operator setting the vacuum to the highest level possible for a certain meat mass. It is noted that a relatively fluid meat mass requires a somewhat reduced level of vacuum as otherwise the meat mass is sucked into the vacuum assembly in an undesirable manner. This “complete evacuation” has as an advantage that the uniformity of the weight of the products is increased significantly and can be kept within relatively narrow tolerances compared to a non-evacuated meat mass.
Weight of the products is not the only parameter that is considered relevant for the products. For instance many parameters, such as texture, bite, juiciness of a meat product once it has been properly prepared for human consumption, e.g. by frying, grilling, cooking, or other heating process, are also considered relevant.